Work Shift - Assumption
Development

© Specific questions on work shift included in
FWMMP questionnaire modules

© Compiled responses of workers who completed
questionnaires

© Used these data to develop assumptions about
probability of working evening or night shift for
each Jobtitle

arent WovngExth SR (Senora by Stntardaot Jobe Chat AD

wy > ee ee

|
ime,
. i ‘orca

)
|

16



Location of Workers

+ Since radon exposure resulted in dispersion of
radon gas from a source, location of workers was
a key parameter in exposure estimation

« 7143 persons ever worked at the site

= 2158 were participants of the Fernald Worker
Medical Monitoring Program, from whom we have
collected detailed occupational history
information (questionnaires and interviews)

Location Assignment Method

- Personnel records did not include location,
except for production workers assigned to a Plant

+ General personnel records misclassified location
for approximately 1/5 of workers for whom
location could be inferred from the records

10




09-25-06P03:30 RCVD

Methods for Radon Exposure
Estimates for Fernald Workers _

Susan M. Pinney, PhD
Department of Environmental Health

Richard Hornung, DrPH

Institute for Health Policy and Health Services
Research

University of Cincinnati

Events leading to research study

- © Excess relative risk for lung cancer.was.found in a mortality

study of workers at the Fernald Feed Materials Plant near
Cincinnnati OH in 1996.

© ACDC dose reconstruction project for estimation of exposures
to residents within 10 km of Femaid indicated relatively high
radon levels off site.

¢ Sources of radon decay products were determined to be two K-
65 silos located on the west side of the plant and used for
storing waste materials including radium.

© NIOSH contracted with the University of Cincinnati to estimate
radon exposures and cigarette smoking rates among Fernald
workers for possible follow-up of the lung cancer mortality study.



‘ree Weting Each Shi (Batapored ry Bandas Job Tele Cars RL

wey

os —
mo

1

|
a

cara snereee 8 Toe

Percant

Percent Working Each Shift (Self-Reported)
by Standardized Job Title Clusters A-G

cal

orm)
losses
loner snl

‘oretng

serncer

Tetacers cre

Cluster of Standardized Joo Teles

7



Exposure Estimation Method

+ Estimate radon exposure at selected site locations
= Specific to calendar year
* Specific to time of day (shift)

K65 exposure + Q11 exposure = Total Radon
Exposure

« Place workers at site locations for each calendar year

+ Assign a probability of working day, evening, night or
rotating shift

« Link radon estimates with annual location assignments
for each worker in the cohort



plant 273

© Interviews with Fernald HP's and retired workers
identified a potential source

© Q-11 silos near plant 2/3 had been used to store
highly radioactive material for later processing

© Several other secondary sources were identified in
the same area

© Search of documents reveals that Q-11 silos were
filled from 1952-58



Overall Area Code - Example

= Overall Area Code — ALL

» 30 location components — with exposure
value specific to each calendar year, and
weighting, specific to each year

Worker Assigned to an Area Location

10: 36831

Hire Date Term Date

1010111951 1011988

Date Plant Dept Job Title Location Code
Code.

40/01/1951 ‘Sec ‘Security Police All

194/27N975 Sec Security Police Officer All

01/16/1978 Sec Police Sergeant AN

14


Radioactive Waste
Shipped to Fernald

» Prior to 1953, large amounts of radium bearing
radioactive waste were shipped to FMPC from
other DOE sites, especially Mallinckrodt Chemical
Works in St. Louis (12,997 drums)

= Drums stored on a concrete pad near Plant 1 until
K-65 silos were completed

» Some drums of K-65 material also stored near
Plant 8 for longer period of time



Summary

—

Deterministic mode! for K-65 source agrees reasonably well with
the 1991 radon measurements (validation study using Carderelli
data)

CR-39 assays indicate a source of radon other than K-65,
probably Q-11 silos, stored raffinate, local processing activities

Final estimates assign high radon exposures to workers in the
plant 2/3 area who were employed from 1952 to 1958

The final product of this study is a matrix of radon exposures for
each Fernald worker by year

Exposures may be used in a future epi study or for
compensation purposes under a current DOL / NIOSH program

Value of FWMMP Occupational History
Questionnaire and Interview Information

= Use of the FWMMP occupational history questionnaire and

interview information allowed us to:

» Much more precisely assign worker location; workers
assigned to multiple buildings rather than a single location

» Assign a probability of having worked the night shift, when
exposures were 2-4 times higher

» Verify and validate our location and shift assignments

Resulted in:

» Wider range of exposures and higher upper bound of the
range

» For compensation: Worker assigned to multiple locations
(each with a different exposure estimate) and shift (separate
matrix for night shift)

26


K-65 Silo - 2003

Radon

© Naturally occurring decay product of 76Radium,
the fifth daughter of 28Uranium

© Both 28Uranium and ?26Radium are found in most
soils and rocks

© Radon decays with a half-life of 3.82 days into a
series of short-lived radioisotopes that are
collectively referred to as radon daughters, radon

progeny and radon decay products.



© STUDY OBJECTIVE: Estimate annual and cumulative
exposures to radon decay products among workers employed at
Fernald site from 1952 to 1988.

© STUDY METHODS (at beginning of study):

© Use deterministic mathematical model developed for the CDC
dose reconstruction project to estimate radon levels across the
site, arising from the K-65 silos.

© jnvestigate and estimate radon exposures from secondary
sources using CR-39 assay of window glass.

© Assign locations of workers; assign a set of shift probabilities to
workers.

© Assign estimated annual radon levels measured in Working
Levels (WL) to workers by their shift and working location in
each year of employment.



PROD ar (een
PA [Pratatane Aa

lauder he prod
SNiettied” ies

etd,

mekie he aed

NG INow-Cotrated area telads noe-provetiow

‘ALL tncladet every location 0 the ste ad wooed

tena ence
nt

May of Areata QveralAre Code |
Ps

(Prod, PA, NC, NC#P, All)

&

Person-years at Each Expasure Estimate Location 1952-1988
Plants 2, 3 and 8 and Surrounding Buildings (332, 45a)

45



Sources of Radon at Fernald
(At time of grant proposal)

» K-65 Silos — held raffinate from processing
ores rich in uranium, which contained
radium

« Radium bearing residues from Mallinckrodt
Chemical Works and other DOE sites

= Approximately 25,000 barrels — into Silo 1

+ Processing of pitchblende ores at FMPC
© During 1950's - residues into Silo 2



Analysis of CR-39 Data

© Po-210 measures were linked to lat/long coordinates
of the building

Weighted multiple regression model was used to
estimate Po-210 levels for each building where
workers were assigned

Weights were a function of wind speed and direction
from Q-11 silos as the point source

Other factors included in the model were building
construction year and inside/outside location of film

Model Results
Polynomial and restricted cubic spline models both fit

log Po-210 data reasonably weil (R? = 0.50-0.53)
24% / year decrease for later construction years

Po-210 levels are 60% less on inside of buildings

Buildings upwind and at a distance from Q-11 silos
were estimated to have exposures one to two orders
of magnitude jower than Q-11 area

Po-210 results were used by the study HP to
calculate Rn exposures in WL by year for each bldg

21


University of Cincinnati Department of Environmental Health
Medical Center University of Cincinnati

PO Box 670056

Cincinnati OH 45267-0056

Delivery Address: _
99-25-96 123 East Shields Street SEC 4h
93:30 Reyy — Cincinnati OH 45220

September 13, 2006

In response to your request, I am providing you with a summary of the methods we used to
estimate radon exposures to Fernald workers, We have given NIOSH a report of our project, as well as a
data file of the estimates. Dr. Hornung and I also are preparing manuscripts to submit to peer-reviewed
journals. I’ve also attached the print outs of a set of slides that I used in reporting to the Fernald
Workers’ Medical Monitoring Program Advisory Group on July 13, 2006.

History of the radon sources at the FMPC site

The Feed Materials Production Center (FMPC) at Femald, Ohio produced uranium metal
products for use in Department of Energy defense programs. From 1953 until 1958, high-grade
pitchblende ore, ie. rock containing very high concentrations of uranium and uranium daughter products,
was used as the raw material for the production of the metal products. This ore was obtained from the
Shinkolobwe mine in the Belgium Congo. Uranium was separated from the pitchblende ore by the use
of the three-phase Purex process: digestion, extraction, and denitration. The aqueous raffinate or waste
from this process was pumped into one of two large concrete silos for storage. These residues, which
were assigned the code name "K-65", contain impurities from the Purex process and all.of the daughter
products of uranium including ”Ra (the parent nuclide of 722Ra) and "Th. The K-65 material was
slurried from the refinery (Plant 2/3) through pipes into one of two storage silos, K-65 Silo #2, located
near the western boundary of the production area.

The radium containing material in K-65 Silo #1 came from another source. Prior to 1953, large
amounts of radium bearing radioactive waste were shipped to the Fernald site from other DOE sites,
especially Mallinckrodt Chemical Works in St. Louis, and eventually stored in the K-65 Silo #1. When.
the waste material first arrived, however, it was placed in sealed metal drums which were temporarily
stored on a concrete pad near Plant 1, resulting in radon gas emissions inhaled by workers in this area.
An internal FMPC memorandum indicates that 12,997 drums of K-65 material were received at the
FMPC in the period September 25, 1951 to July 31, 1952. Other drums of K-65 material were stored in
Plant 8 for long periods of time. Eventually the drummed material was transferred to Silo #1 when it
was completed and ready for operation.

The K-65 silos, located on the western edge of the production area, were constructed in 1951 to
1952, and materials were added to the silos from July, 1952 to September, 1958. The silos had problems
with deterioration almost since the time of construction. Significant cracking in the walls and seepage of
the contents was noted from the 1950's. Because of these problems, periodic repairs and improvements

1
Patient Care * Education « Research * Community Service
An affirmative action/equal opportunity institution



Pitchblende Ore Processing

« Uranium separated from ore by 3-phase Purex
process: digestion, extraction and denitration

= Aqueous raffinate or waste contained all daughter
products from uranium and impurities including
268Radium (the parent nuclide of 2#Radon)

» Assigned code name K-65

« Pumped into large concrete silo for storage (K-65
silo)



Pitchblende Ore Processed at
Fernald from 1952-1958

« Rock containing very high concentrations of
uranium and uranium daughter products
(including radium).

« Received at FMPC from mine in the Belgian
Congo (Shinkolobwe mine).

+ Code name Q-11; Stored in Q-11 ore silos near
Plant 1



Uranium Decay Chain

Isotope. Halla Radiation
Uranhum-238 | 4800,000,000 years pha
Thorium 24 Dans ew gare
Prataetnban 236m, 12 mirwien ete, gue
eamumaae 750,600 years ‘ioha, game
Trortane 230 30,000 years ‘aiphe, gare
Rasilum228 TSP yore ‘ipha, oar
Raton'222 aaa cs
Potorwun-216 as einen aighe
Tons 262 minutes bets, gamma
Asiatine 218 Zo seconds aehe
Bima 2 197 mints ‘beta, gamma
Polonium-ate | 0000304 eecends | _aiphe, amma
Thain Tamieutes bea gene
Laadat0 Ryn bate, game
Sismoin20 today Bete
Polontunr210 adays ‘aipha, gamma |
Thaihune206 “aie ven |
teats tbe ved

Health Effects of Radon

» When radon progeny are inhaled and release
alpha particles within the lungs, the cells lining
the airways receive genetic damage, and
ultimately lung cancer may result.

« Combined risk of smoking and radon ~ more than
additive, less than multiplicative.

+ Radon also know to increase risk of cataracts



GR-39 Assay

© CR-39 is a plastic film taped to window glass for about 3 weeks
in buildings on site to record polonium-210 alpha activity, a
primary radon decay product.

© Glass in place throughout the plant history serves as a
cumulative radon dosimeter.

© CR-39 assay was developed at the University of Bristol and
used in case-control studies of lung cancer and radon in homes,
but never in an industrial, highly contaminated setting.

CR-39 Assay

¢ Decided to use CR-39 assay to validate
estimates from mathematical deterministic
model.

¢ Asked NIOSH for funding

© Pilot study — 20 samples

© Main study — 80 samples

¢ Additional study — another 31 samples

© 131 CR-39 plastics were placed on both
inside and outside of glass panes in buildings
throughout the plant.

18


Mean and Highest Yearty Wosker Radon Exposure Estimates (WLM)
due to K-65 source

°
PILI LL LLL E ELE EPP LIOS

vee

Mean and Highest Yearly Worker Radon Exposure Estimate (WLM)
due to Q-14 source

. :
SPH PEPSI FE EEEESFESEE

=

24


Assignment of worker locations and shift

The most important factors for determining worker radon exposure for this cohort (N=7142) were
location of the worker and shift worked (because of diurnal variation in radon levels). Personnel
records did not include this information. Historical records and information from worker interviews
and questionnaires (from a subset of the cohort) were used to assign worker location for various
combinations of Plant, department, and job title noted on the personnel record. Shift was assigned on
the basis of standardized job titles. Questionnaire data regarding shift worked for specific job periods,
available for 1207 workers, were used to determine a set of probabilities of shift assignment for
clusters of job titles. The worker’s locations were linked with the matrices of yearly exposure
estimates by location specific to shift, and estimates for each shift were weighted by the shift
probabilities assigned to the worker. For the 1207 workers who were asked shift information on their
questionnaires, we also calculated a second set of radon estimates using their self-reported information.
Location and shift assignment have been validated using historical sampling records and other
questionnaire data, not used in assumption development.

Radon estimates:

As might be expected, the estimated radon estimates from the K-65 source generally declined over
time with a dramatic drop after 1979 when the silos were capped. The distribution across workers
within each year ranged from slightly skewed, generally following a lognormal distribution, to fairly
symmetrical. The exposures from the Q-11 source, on the other hand, are essentially bi-modal. The
workers who were located in buildings in close proximity to the Q-11 silos are estimated to have
relatively high radon exposures, while workers in buildings farther from the source are exposed at
much lower levels. Yearly mean day-shift worker exposure attributable to the K-65 source term ranged
from 0.002 to 0.085 WL. By contrast, yearly mean exposure to workers on the day shift in the area of
the Q-11 silos ranged from 1.3 WL to 7.8 WL from 1953-1958. Worker cumulative exposure from the
K-65 source ranged from 0.0 — 51.8 WLM, median 1.5 WLM; curnulative exposure from the Q-11
source ranged from 0.0-700.1 WLM, median 2.6 WLM. The 90" percentile cumulative radon
exposure from K-65 was 18.06 WLM and from Q-11 source was 31.52 WLM.

. Lhope this provides you with the information you need for your Special Exposure Cohort application.
Please contact me if you have any questions.

Susan M. Pinney, PhD
Associate Professor


Location Assignment Method

+ Obtained file of job history (multiple record per
person. file) from NIOSH— each record contained
lant, Department and Job Title information for

periods of employment, with beginning and end
dates,

© For some workers, no work location could be
inferred from information in personnel records:

« Mechanical Division (electricians, carpenters,
machinists, etc.)

= Laboratory Division

« Inventory and time clerks who worked in
offices in the production plants, and

« Workers in the Security division

Work Location Assignment

= We developed a series of assumptions regarding
work locations for combinations of plant,
department and job title, using records such as
FWMMP occupational history questionnaire and
interview information, union contracts, and
position descriptions.

» Each record of the worker's job history was then
assigned a location code, indicating one or
several work locations for that time period.

11


Work Location Code — linked to multiple
exposure estimate locations

* “Single location” code - Plant 2/3
* 66% Building 2A — Ore Refinery Plant
» 10% Building 2D- Metal dissolver bullding

* 7% each Buildings 3C, 3E and 3H — Control Tower, Hot
Raffinate Building, Refinery Sump

= 3% Building 39A ~ Incinerator Building

« Combination code - ANDBLDG15,P
= 60% Building 15a - Laboratory

= 40% P [Production Area]- many buildings in the
production area

Overall Area Codes for Some Workers

= Some job titles known to work at a variety of
areas throughout plant site

- For other job titles, insufficient information to
assign them to a specific location.

» Developed “area” codes

+ Multiple exposure estimation sites linked to each
area, weighted by number of employees, with
specific or combination location assignment,
assigned to that location in that calendar year.

13


was done between 1988 and 1991, we assumed that results should be comparable. The estimates were
in reasonably good agreement to Cardarelli’s measurements.

Our second attempt to validate the model was the use of CR-39 film attached to windows in
selected buildings around the site. The CR-39 film measures alpha activity from the decay of Pb-210,
auranium decay product which was embedded in the glass over several decades. This assay, therefore,
serves as a cumulative measure of radon and its decay products since cach building was constructed.
We assumed that the glass was the original window pane. We attempted to select windows that
appeared to be weathered and were located high enough that they were less likely to have been broken.
A pilot survey of 20 surface monitors was sent to Dr. Fews at the HH Wills Physics laboratory in
Bristol, England. Results indicated very small replicate error and good ability to measure radon alpha
tracks (Po-210) on both low and high exposed buildings. In the pilot study, we were surprised to
discover very high values for some of the glass. With NIOSH support, we expanded our sample size to
110 samples placed throughout the site on buildings selected for their proximity to both the K-65 silos
and the plant 2/3 area where we found the initial high measurements.

Results of the larger survey indicated that glass sampled in the plant 2/3 area were substantially
higher than glass closer to the K-65 silos. Once we became aware of these CR-39 findings, we
conducted additional document searches and met with workers several times to develop a better
understanding of this local source of radon. The Q-11 silos, close to the Plant 2/3 area, had been used
in the period 1953-58 to store highly grade ore before it was processed in the Plant 2/3 complex.
Although the amount of material was considerably less than that stored in the K-65 silos, the Q-11
silos were much closer to the production area and were not sealed. The hot raffinate by-product of the
chemical separation of high grade uranium also was handled and temporarily stored in the Plant 2/3
area. In addition, drums of similar waste product from Mallinkrodt Chemical Works were stored on a
pad near Plant 1, directly north of the Q-11 silos.

Because of the potential for much higher exposures to workers in the Plant 1 and Plant 2/3 area
employed during the period 1952-58, we decided to develop a statistical prediction mode] with Q-11 as
the point source. Input variables in this model included CR-39 Po-210 results by building, distance
and direction from each building to the Q-11 silos, average wind speed and direction by year, and
construction year for each building.

The results of this prediction model were the input data for use by our health physicist, Jeff
Lodwick, to calculate radon decay product exposure estimates in Working Levels (WL) from the Po-
210 estimates. Through historical documents and interviews of retired workers, we determined that Q-
11 and the drummed material on the Plant 1 storage pad were present only for the period 1952-58, for
4153 workers employed at the site during those years. Dr. Lodwick used knowledge of decay product
half-lives and the number of years between CR-39 measurements and the period of interest, to
calculate annual WL levels for each building within reasonable proximity of the Q-11 silos. Buildings
at a large distance from the Q-11 silos were used as a calibration background for the other estimates
and were assigned zero exposure from the Q-11 source. All of these background buildings
demonstrated very low levels of Po-210 alpha tracks in the CR-39 measurements. Using locations at
distant buildings as calibration background produced estimates of radon exposures solely from the Q-
11 source, even though the CR-39 film would have also recorded radon released from the K-65 silos.
The total yearly radon exposure for each worker was then obtained by summing the contributions from
each source,




to the Silos were implemented from the 1960's through the 1980's. Two components were added to
maintain structural stability. Embankments or berms (built in 1964 and enlarged in 1983) were built to
relieve tensile stress in the vertical walls and to protect against deterioration of the concrete. The berms
also acted as direct radiation shields. Placement of protective dome covers in 1970’s, constructed of steel
and plywood, blanketed the center of each silo. By themselves, the covers offered little if any barrier to
the diffusion and ventilation of radon. Vents in these domes were sealed in 1979. In 1986, a waterproof
protective membrane of liquid neoprene was added, and in 1987 a layer of polyurethane foam was placed
on dome surface in an attempt to mitigate the migration of radon gas to the environment. No routine
environmental monitoring for radon was performed prior to 1980.

A cohort mortality study of Femald workers, conducted by Dr. Donna Cragle, reported a
significant excess of lung cancer deaths among hourly workers (Standardized Mortality Ratio=1.26, 90%
confidence interval 1.02, 1.54), with a borderline significant trend (p=0.08) in increase in risk with
extemal radiation dose. Suprisingly, there was no correlation with internal radiation dose, which would
have been an expected finding. Because there was a radon point source, but only limited air monitoring
data from recent years, a radon exposure reconstruction was necessary to obtain lung cancer risk
estimates.

Radon Exposure Estimation:

In our grant application to NIOSH, we proposed to extend the K-65 Silo radon dispersion
model, developed by RAC for the 10 kilometer community exposure domain, to the inside the fence
line for the Fernald plant site. George Killough, the model's principal developer, assured us that the
model would be accurate for worker locations. As a consultant on this project, he produced radon
estimates for latitude and longitude coordinates supplied to him by our University of Cincinnati team.
These sets of geographical coordinates represented the centroid of each of the buildings on the site
occupied by workers. We did additional analyses to estimate the diurnal variation in exposure,
significant at the site, as well as the decrease in emissions with the capping of the K-65 silos. For all
specified locations, we calculated yearly night and day exposure estimates.

Similar to.the community-based dose reconstruction, Killough’s worker model was based upon
distance from the K-65 silos, wind speed and direction, and the radon source term. Because of the
diurnal variation, we requested that Killough develop radon estimates for each of the three shifts for
each calendar year. This was an important difference from the original RAC model, but necessary for
the application to worker exposure estimates, because it has been well-established that outdoor radon
levels peak in the early hours of the morning when atmospheric conditions are usually calm.
Therefore, the estimates that we provided for NIOSH are weighted by shift, either reported directly by
the worker or assigned to workers based upon average shift distributions for other workers in their
departments and time periods.

Model validation

Since the RAC model is a conceptual mathematical model developed from physical principles
and is not based directly upon measured data, we attempted in two ways to investigate the accuracy of
its estimates. First, we discovered radon measurement data that had not been used by the RAC group
to calibrate their model. These were data collected by John Cardarelli for his Master’s thesis during
the period of March through September 1991. Data were collected both in the immediate vicinity of
the K-65 silos and at various points around the production area. We then compared Cardarelli’s
measurements by shift and location to the closest year of our estimates, 1988. Since no remediation

2


Distribution of Cumulative Total Radon Exposure (WLM)
from the K-65 Source

|
|

=

; |

oP eC EMENHU RTA KEN HBR EM HOHE w
‘Cumulative K-66 (WLM)

aa TI

Distribution of Cumulative Non-Zero Raden Exposure (WLM)
from the Q-14 Source

cont
s 2?
|

&
ae



CDC Fernald Dosimetry Reconstruction
Radon Release Estimates

1952-1953 K-65 Silos 1900 Ci

Drummed waste —_720 Ci
1953-1958 K-65 Silos 4900 Cilyr
1959-1979 K-65 Silos 6200 Cilyr
1980-1987 K-65 Silos 940 Cilyr
1988 K-65 Silos 230 Ci

CDC/RAC Deterministic Model

© Model was developed to estimate radon levels
outside the Fernald plant site

© Model was based on physical and mathematical
principles, such as emission rates from K-65 silos,

plume dispersion from a point source, meteorological
conditions, and engineering controls

© Data were only used to calibrate the model

¢ Output of model was 24-hr average exposures to
residents within 10-km radius of K-65 silos



Worker Assigned to a Specific Building

1D: 34076
Hire Date Term Date
44711954 (01/17/1957
Date Plant Dept Job Title Location
Code Code
sin7H984 = 2 Prod Laborer Plant 2/3
09/26/1955 3 Prod Chemical Operator Plant 23
Helper
oa2ness = 3 Prod Chemical Operator Plant 2/3
11091956 «3 Prod Laborer Plant 213
Worker Assigned a Combination Code
ID: 37484
Hire Date ‘Term Dato

08/01/1962 ovot1e83

Date Plant Dept Job Title Location Code
Code

08/01/1952 Anal_—=— Tech Technologist B ANDBIdg15,P

401011955 Anal Tech Technologist Il ANDBIdg15,P

08/27/1956 Anal Tech ‘Section Leader! Bidgi5+P

09/21/1959 Anal = Tech Sedion Leader it BidgiS+P

05/01/1972 Anal = Tech Technologist Il ANDBIdg15,P-

12